We are examining the following reactions which occur during the metabolism of aromatic compounds: (1) The N-hydroxylation of L-tyrosine that occurs when L-tyrosine is converted to p-hydroxyphenylacetaldoxime by a microsomal preparation from etiolated sorghum shoots. (2) The Beta-hydroxylation of p-hydroxyphenylacetonitrile that is catalyzed by sorghum microsomes. (3) The hydroxylation of cinnamic acid in the 2-position that is catalyzed by sweet clover chloroplasts. The further hydroxylation of the o-coumaric acid will be examined. (4) The deamination of L-phenylalanine by clover chloroplasts.